Often it is desired to moor a ship .Iadd.or other buoyant floating structure .Iaddend.generally over a fixed location on the water bottom. This is particularly true in off-shore well drilling operations and is especially difficult to accomplish in deep water. Further, as wind direction and wind intensity change, it is often necessary or desirable to re-orient floating vessels to face into the wind or in some other desired direction while maintaining a position generally over the fixed location on the water bottom.
A variety of mooring methods and apparatus have been used and described in the literature. Some methods involve elaborate schemes of positioning anchors and anchor lines. Another method involves the use of air cushioning devices and a circular superdeck. Other methods envision the use of a well which extends vertically through the vessel and through which are passed a plurality of anchor lines.
The following patents illustrate various types of ship mooring methods and apparatus.
______________________________________ U.S. Pat. No. Issued Class Inventor ______________________________________ 3,191,201 6-29-65 9/8 Richardson et al. 3,461,828 8-19-69 114/.5 Bielstein 3,525,312 8-25-70 114/.5 Beck et al. 3,590,407 7-6-71 9/8 Bratiann et al. 3,552,343 1-5-71 114/.5 Scott 3,620,181 11-16-71 114/.5 Naczkowski 3,583,354 6-8-71 114/206 Flickinger 2,919,671 1-5-60 114/230 Knapp et al. 3,440,671 4-29-69 9/8 Smulders 3,279,404 10-18-66 114/.5 Richardson ______________________________________
Each system has its own advantages and disadvantages. For example, with some prior art systems the method of use is so cumbersome as to be impractical. Other systems are expensive and can be readily incorporated into ships and other vessels only during original construction.
There exists a continuing need for alternative methods and apparatus for mooring vessels generally over a fixed position on the water bottom. In particular, there exists a need for a ship mooring method and related apparatus which can be used with and incorporated into existing vessels without major structural alteration or modifications.